0.125×0.25×32
1500-18×120÷25
×101-0.75
÷[
×(0.4+
)]
÷[(
+
)×
].解:(1)0.125×0.25×32,=0.125×0.25×4×8,
=0.125×8×(0.25×4),
=1×1,
=1;
(2)1500-18×120÷25,
=1500-86.4,
=1413.6;
(3)
×101-0.75,=0.75×101-0.75,
=(101-1)×0.75,
=100×0.75,
=75;
(4)
÷[
×(0.4+
)],=
÷[
×(
+
)],=
÷[
×
],=
÷
,=
×
,=
;(5)
÷[(
+
)×
],=
÷[
×
],=
÷
,=
×
,=3.
分析:(1)把32看作4×8,运用乘法交换律与结合律简算;
(2)先算乘除,再算减法;
(3)把分数改为小数0.75,运用乘法分配律简算;
(4)(5)题先算小括号内的,再算中括号内的,最后算括号外的.
点评:此题考查了四则混合运算.注意运算顺序和运算法则,灵活运用所学的运算定律简便计算